[PROJ] Is your the geoid model from your country in PROJ?

[Javier Jimenez Shaw]

On Fri, 12 Apr 2024 at 16:31, Howard Butler <howard at hobu.co> wrote:

>
>
> > On Apr 12, 2024, at 5:56 AM, Javier Jimenez Shaw via PROJ <
> proj at lists.osgeo.org> wrote:
> >
> > Maybe you want to talk with your local agency to fix this ;)
>
> It is not always clear as a motivated-but-unconnected individual which
> local agency and person inside it to contact to sort things out.

That is the first step, true. Contact details in the webpage of the agency
sometimes work. If not, networking is the key. Ask to your network if
anybody knows somebody in that agency. They are usually not that big (not
that many people is in geodesy). That's why I am asking here: it is much
easier for locals to reach that people. Speaking the local language also
helps.


> It is also often the case that some government officials might not feel
> they have the power to change the license

I see. But many times it is simpler than expected. Just asking works to
change to a valid license. Other times they can use two licenses. For
instance the author changed the license in
https://www.isgeoid.polimi.it/Geoid/America/Argentina/argentina2016_g.html
Also some clarifications are useful. In some pages it is simply not clear
the license that applies, because nobody cared before. I was very happy
that Portugal quickly made it explicit CC BY 4 when I asked that.


> or releasability of a model.

That can be a problem. I know some countries that are afraid of that. But
showing how many other countries are releasing their models could help. It
is also information needed by the citizens/companies of that country.
Keeping it secret destroys the purpose of such a tool.

Finally, getting an official grid to PROJ CDN might require navigation of
> the procedures of a specialized geospatial standard body (EPSG) and
> standards conformance of those grids before official registration.
>
Fortunately geoid models are simple to register, and EPSG is usually quick
including this kind of requests. There are several grids just as an ascii
file with "lat, long, undulation". Not the most compact format, but easy to
understand (recently I explained to an agency how to use GDAL to manage
those formats. They were very happy!). See that the geoid model file is not
uploaded to EPSG, but just mentioned (as a filename). The agencies are
"responsible" of making it accesible (something not always the case).


>
> A step-by-step process document written by people who have completed it
> would be a helpful guide of all the various starting points and steps.
>
> There is already some documentation in
https://github.com/OSGeo/PROJ-data/blob/master/CONTRIBUTING.md , but it's
true it starts when you have all the data. I will make a PR trying to
explain the previous processes based on my experience adding some geoid
models there.

In any case I am happy to help anybody that wants to add a grid file to
PROJ. If you have data or contacts, just contact me in this mailing list or
personally.

Cheers,
Javier.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20240413/7aaea5ae/attachment.htm>